drivers: PL011: refactor pl011_probe()

Currently the pl011_probe() function is relying on some AMBA IDs
and a device tree node to initialize the driver and a port.
Both features are not necessarily required for the driver:
- we lack AMBA IDs in the ARM SBSA generic UART and
- we lack a DT node in ACPI systems.
So lets refactor the function to ease later reuse.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 61 insertions, 35 deletions

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 686951a19716..38d2245d7485 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2173,65 +2173,54 @@ static void pl011_unregister_port(struct uart_amba_port *uap)
                 uart_unregister_driver(&amba_reg);
 }
 
-static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
+static int pl011_find_free_port(void)
 {
-        struct uart_amba_port *uap;
-        struct vendor_data *vendor = id->data;
-        void __iomem *base;
-        int i, ret;
+        int i;
 
         for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
                 if (amba_ports[i] == NULL)
-                        break;
-
-        if (i == ARRAY_SIZE(amba_ports))
-                return -EBUSY;
+                        return i;
 
-        uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
-                           GFP_KERNEL);
-        if (uap == NULL)
-                return -ENOMEM;
+        return -EBUSY;
+}
 
-        i = pl011_probe_dt_alias(i, &dev->dev);
+static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
+                            struct resource *mmiobase, int index)
+{
+        void __iomem *base;
 
-        base = devm_ioremap(&dev->dev, dev->res.start,
-                            resource_size(&dev->res));
+        base = devm_ioremap_resource(dev, mmiobase);
         if (!base)
                 return -ENOMEM;
 
-        uap->clk = devm_clk_get(&dev->dev, NULL);
-        if (IS_ERR(uap->clk))
-                return PTR_ERR(uap->clk);
+        index = pl011_probe_dt_alias(index, dev);
 
-        uap->vendor = vendor;
-        uap->lcrh_rx = vendor->lcrh_rx;
-        uap->lcrh_tx = vendor->lcrh_tx;
         uap->old_cr = 0;
-        uap->fifosize = vendor->get_fifosize(dev);
-        uap->port.dev = &dev->dev;
-        uap->port.mapbase = dev->res.start;
+        uap->port.dev = dev;
+        uap->port.mapbase = mmiobase->start;
         uap->port.membase = base;
         uap->port.iotype = UPIO_MEM;
-        uap->port.irq = dev->irq[0];
         uap->port.fifosize = uap->fifosize;
-        uap->port.ops = &amba_pl011_pops;
         uap->port.flags = UPF_BOOT_AUTOCONF;
-        uap->port.line = i;
+        uap->port.line = index;
 
-        /* Ensure interrupts from this UART are masked and cleared */
-        writew(0, uap->port.membase + UART011_IMSC);
-        writew(0xffff, uap->port.membase + UART011_ICR);
+        amba_ports[index] = uap;
 
-        snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
+        return 0;
+}
 
-        amba_ports[i] = uap;
+static int pl011_register_port(struct uart_amba_port *uap)
+{
+        int ret;
 
-        amba_set_drvdata(dev, uap);
+        /* Ensure interrupts from this UART are masked and cleared */
+        writew(0, uap->port.membase + UART011_IMSC);
+        writew(0xffff, uap->port.membase + UART011_ICR);
 
         if (!amba_reg.state) {
                 ret = uart_register_driver(&amba_reg);
                 if (ret < 0) {
-                        dev_err(&dev->dev,
+                        dev_err(uap->port.dev,
                                 "Failed to register AMBA-PL011 driver\n");
                         return ret;
                 }
@@ -2244,6 +2233,43 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
         return ret;
 }
 
+static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
+{
+        struct uart_amba_port *uap;
+        struct vendor_data *vendor = id->data;
+        int portnr, ret;
+
+        portnr = pl011_find_free_port();
+        if (portnr < 0)
+                return portnr;
+
+        uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
+                           GFP_KERNEL);
+        if (!uap)
+                return -ENOMEM;
+
+        uap->clk = devm_clk_get(&dev->dev, NULL);
+        if (IS_ERR(uap->clk))
+                return PTR_ERR(uap->clk);
+
+        uap->vendor = vendor;
+        uap->lcrh_rx = vendor->lcrh_rx;
+        uap->lcrh_tx = vendor->lcrh_tx;
+        uap->fifosize = vendor->get_fifosize(dev);
+        uap->port.irq = dev->irq[0];
+        uap->port.ops = &amba_pl011_pops;
+
+        snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
+
+        ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr);
+        if (ret)
+                return ret;
+
+        amba_set_drvdata(dev, uap);
+
+        return pl011_register_port(uap);
+}
+
 static int pl011_remove(struct amba_device *dev)
 {
         struct uart_amba_port *uap = amba_get_drvdata(dev);